feat(ui): 15-minute aggregation collapses repeated subnet-activity rows

[JSONbored]

Closes #8366 — with a documented scope note posted first (#8366 (comment)): the shared-hook subscription and scoped LIVE affordance were already shipped (#8445/#8452, hardened by #8365); this PR is narrowly the one remaining requirement — the 15-minute aggregation rule itself.

What changed

aggregateActivityEvents (new, pure, unit-tested directly): groups CONSECUTIVE same-kind events — adjacent in the given newest-first order — into one row once they land within 15 minutes of the group's newest member. "Consecutive" is literal: a same-kind event that resumes after a different kind interrupts it starts a fresh group rather than retroactively merging into an earlier occurrence. An event missing observed_at never joins a group — no timestamp to prove the "within 15 minutes" claim.

Runs over whatever events array ActivityTableLoader already has — refreshed by a live stream event or the existing poll alike — so there's exactly one rendering path for both modes, per the issue's own text.

ActivityGroupRow: a group of one renders through the extracted ActivityEventRow completely unchanged (byte-for-byte identical to every row before this PR). A group of more than one collapses to a summary row — EventKindCell's own "× N · last Mm" (the issue's worked-example format), the newest member's block/time, and the shared hotkey when every member has the same one ("multiple" otherwise) — clickable to reveal the individual member rows nested beneath it.

Verified against live data

Confirmed against real production data via a running dev server: a genuine repeated-kind run ("Stake added × 4 · last 1m") collapses correctly, and clicking it expands to exactly 4 nested rows (row count 80 → 84, aria-expanded toggling false → true).

This also surfaced something worth knowing, flagged on the issue rather than worked around: this subnet's actual weight-setting traffic alternates "Timelocked weights revealed" and "Weights set" strictly back-to-back, so literal same-kind-adjacent grouping doesn't collapse that specific interleaved pattern — each kind interrupts the other before either repeats. That's the spec's own "consecutive" wording working exactly as written, not a bug — but it means the single most repetitive real pattern on this subnet isn't the one this aggregation shrinks. A "commit+reveal pair" heuristic would be a materially different, more speculative policy than what was asked for, so I didn't silently expand scope to cover it.

Not attempted here (noted on the issue): the entrance-animation portion of requirement 4 — a separate, smaller polish item for a follow-up rather than bundled into an already-substantial change. Requirement 4's other pieces (visibility gating, no per-row timers, fallback DOM parity) are already covered by #8365 for this same table.

Screenshots

Viewport · Theme	Before	After
Desktop · Light
Desktop · Dark
Tablet · Light
Tablet · Dark
Mobile · Light
Mobile · Dark

The desktop-light "after" shows a real collapsed row in the captured data ("Stake added × 2 · last 0m" with the collapse chevron) — the expand/collapse interaction itself (screenshots can't show a click) was verified directly against the DOM as described above.

Validation

npm run lint --workspace=apps/ui            # 0 errors
npm run format:check --workspace=apps/ui    # clean
npm run typecheck --workspace=apps/ui       # clean
npm test --workspace=apps/ui                # 1650 passed, 1 skipped (11 new)
npm run test:e2e --workspace=apps/ui        # 40 passed
npm run build --workspace=apps/ui           # clean

No API, schema, or generated-contract surface touched.

[loopover-orb]

Important

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_{🟩 Safe / merged · 🟦 Advisory · 🟨 Held for review · 🟥 Blocked / closed · 🟨 Waiting}

[superagent-security]

Superagent didn't find any vulnerabilities or security issues in this PR.

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	metagraphed-ui	a71cdcc	Commit Preview URL Branch Preview URL	Jul 28 2026, 05:12 AM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.82%. Comparing base (edee55a) to head (a71cdcc).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

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  Coverage   97.82%   97.82%           
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  Files         419      419           
  Lines       29179    29179           
  Branches    10958    10958           
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  Hits        28545    28545           
  Misses        143      143           
  Partials      491      491           

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